Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [FA-1 TOPOGRAPHIC ANALYSIS]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Combined Application of Pattern Recognition Methods in Automatic Digitization of Contour Line Maps. Jun Yang

Document type:: Multivolume work

Structure type:: Chapter

809 Combined Application of Pattern Recognition Methods in Automatic Digitization of Contour Line Maps Jun Yang The Digital Elevation Model (DEM) has been applicated more and more in spatial analysis, regional planning, project designing, topographical displaying etc. Many governmental and private institutions are engaged to gather digital elevation information from different sources. The digitization of existing maps is a highly efficient and economic way-, if the qualities of the maps are sufficient. But the most used manual method of digitization cannot cover the increasing require ments. Therefore a system has been developed to automatic structuring of con tour line maps from scanned data. The system has been tested in the Institute of Cartography, University of Hannover. A contour line map usually contains three kinds of information: 1. the contour lines, many of which are drawn in regularly dashed lines, 2. the numbers showing the heights of the contour lines and 3. the special symbols describing the sudden change of the terrain, such as cliffs and outcrops. This system is composed of the following procedures: Scanning and vectorization. A map is transformed into image by a scanner. The raster data have to be converted into vector data in order to reduce the data and accelerate the processing. Segmentation of contour lines from texts and symbols. At first all kinds of data are in one level. The recognitions can be carried out only succesively and me thods used for every kind of object are different. Therefore it is neccesary to separate the data into different object subset before classification. To distingu ish the different objects the features which contain the characteristic informa tions, e.g. line length, line width, line curvature and number of lines on nodes, are extracted. Upon this feature space a training process should be effected to get the parameters that will be used in classification. At first step the contour lines are selected from another data set by means of Quader Classification me thod . Recognition of contour lines. The contour lines for example in Germany Basic Map Series 1:5000 were drawn in dashed lines excepting the contour lines at the 10 meters vertival interval. The different line width, line length and gap length have been used to construct the line signatures for representing different vertival interval. The line signatures have the defined structures.

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